The present invention relates to a jig saw blade, especially for heavy duty work, such as sawing through hard materials, for example, building walls of concrete or masonry. Such blades are conventionally provided with hard metal or diamond inserts along their cutting edge. The invention also relates to a method of producing a heavy duty jig saw blade.
Substantial difficulties have been encountered heretofore in the proper cooling of heavy duty jig saw blades, which are used for cutting holes into concrete walls or the like. On the one hand it is desirable to operate the jig saw with a high cutting speed to keep the time necessary for producing a certain cutting length as small as possible. On the other hand it has been difficult to avoid the large heat generation resulting from increasing cutting speeds. Such heat generation may be so high that the saw blade will eventually be destroyed. The supply of cooling water to the upper end of a jig saw blade has been found to be insufficient, because the cooling water does not reach those parts of the blade remote from the tool holder head, because of evaporation.
Further, the supply of a cooling medium to the outside of the blade is usually not effective when the blade extends horizontally to cut a slot into a vertical wall. Another difficulty in providing an efficient cooling is seen in that the saw blade has a rather narrow dimension across the cutting direction to keep the slot to be cut narrow. This given shape of jig saw blades makes it impossible to secure a hose or the like to the blade for supplying a cooling liquid as is possible in connection with rotating tools.